The invention relates to a form cylinder of a web-fed rotary press.
Web-fed printing presses, in particular newspaper presses, have a plurality of printing units, each printing unit having, inter alia, at least one form cylinder and at least one transfer cylinder. Printing plates are fastened on the form cylinders and rubber blankets are fastened on the transfer cylinders, for which reason the form cylinders are also referred to as printing plate cylinders and the transfer cylinders are also referred to as blanket cylinders. A transfer cylinder interacts with every form cylinder in such a way that, during printing, a form cylinder rolls on the respective transfer cylinder. Accordingly, there is rolling contact during printing between the form cylinders and the transfer cylinders. During printing or while the form cylinders are rolling on the respective transfer cylinders, cylinder oscillations can form which impair the printing quality. Accordingly, cylinder oscillations have to be minimized in order to ensure satisfactory printing quality.
Proceeding from this, the present invention is based on the problem of providing a novel, oscillation-minimizing form cylinder of a web-fed rotary press.
According to the invention, a clamping channel of the form cylinder has an effective clamping-channel width of at most 7 millimeters (mm), as seen in the circumferential direction. Cylinder oscillations which occur during printing can be reduced considerably by adapting the clamping-channel width to less than 7 mm.
As seen in the circumferential direction, the clamping channel of the form cylinder has an effective clamping-channel width of from 3 mm to 7 mm. In the context of the invention, the following ranges are preferred for the effective clamping-channel width between 3 mm and 7 mm: from 3 mm to 6 mm; from 3 mm to 5 mm; from 3 mm to 4 mm; from 4 mm to 7 mm; from 4 mm to 6 mm; from 4 mm to 5 mm; from 5 mm to 7 mm; from 5 mm to 6 mm; and from 6 mm to 7 mm.